Mobile communications devices have become an integral part of society over the last two decades. Indeed, more than eighty-two percent of Americans own a mobile communications device, for example, a cell phone. The typical mobile communications device includes an antenna, and a transceiver coupled to the antenna. The transceiver and the antenna cooperate to transmit and receive communication signals.
The typical mobile communications device includes a plurality of switches for permitting the user to operate the device conveniently. For example, the switches may be arranged in the traditional keypad orientation, i.e. a numeric keypad or utility keypad on the side of the device. The switches are coupled to a circuit board within the device and are carried by the housing of the mobile communications device, extending through openings in the housing. Since the typical user subjects the mobile communications device to a wide variety of environmental conditions, manufacturers typically enclose the switches with a sealing membrane made of, for example, rubber or silicone. The sealing membrane not only seals the switches within the housing but also provides a good tactile surface for the user to manipulate.
An approach to the sealing membrane is disclosed in U.S. Pat. No. 5,270,499 to Marchuk et al. This sealing membrane includes a body portion covering the respective switch, and a flange portion coupled thereto and being compressed by a front grill and a housing for the device, thereby defining a seal. The flange portion is V-shaped and, while compressed, provides an area of high-pressure.
In some applications, it may be desirable to provide a mobile communications device that can reliably operate in humid and wet environments, for example, underwater environments. In these applications, the housing of the device provides a waterproof barrier and any openings, for example, those provided for access to switches, are sealed to be watertight, i.e. the sealing membrane provides a watertight seal. Further, in these applications, the typical sealing membrane may include a flange portion installed into the device using adhesive material adjacent the flange portion to create the watertight seal.
This adhesive material approach may suffer from certain drawbacks. For example, the adhesive material may deteriorate over time, thereby causing the watertight seal to fail after a certain period of use. This can be especially problematic for the user if this failure occurs in the field since the mobile communications device will likely fail to operate. Moreover, during manufacturing, the application of the adhesive material is a time intensive process that adds cost to manufacturing. Moreover, the quality of the watertight seal provided by the adhesive material is directly related to the integrity of its continuous and consistent application during manufacture, which can provide a less than desirable yield rate. Also, if the mobile communications device needs to be serviced, the adhesive material is typically removed or destroyed to open the device, thereby adding cost and time to the repair process. Lastly, the adhesive material approach may not provide a watertight seal in depths greater than twenty meters.